Electron Capture - X-ray or gamma-ray?

[rwooduk]

I may be being a bit pedantic but when an electron "falls" (or is captured by) into the nucleus, does the outer shell electron that fills its place result in an x-ray or a gamma-ray being emitted? Or would it depend on the energy transition?

Thanks for any ideas.

 

[davenn]

I may be being a bit pedantic but when an electron "falls" (or is captured by) into the nucleus, does the outer shell electron that fills its place result in an x-ray or a gamma-ray being emitted? Or would it depend on the energy transition?

Thanks for any ideas.

from Wiki ...

Since a proton is changed to a neutron during electron capture, the number of neutrons in the nucleus increases by 1, the number of protons decreases by 1, and the atomic mass number remains unchanged. By changing the number of protons, electron capture transforms the nuclide into a new element. The atom, although still neutral in charge, now exists in an excited state with the inner shell missing an electron. An outer shell electron will eventually transition to fill the missing inner electron thereby dropping to a lower ground state. During this process, that electron will emit an X-ray photon (a type of electromagnetic radiation) and other electrons may also emit Auger electrons. Often the nucleus exists in an excited state as well, and emits a gamma ray as it transitions to the ground state energy of the new nuclide.

does that answer you Q ?

Dave

 

[rwooduk]

from Wiki ...

does that answer you Q ?

Dave

Hmm, sorry should have checked Wiki. Yes very helpful, thankyou!

 

[davenn]

no probs, you are welcome

 

[ChrisVer]

In general, keep in mind, that electron shell transitions don't produce gamma rays but X-rays... The transitions of nuclei are the ones producing gamma rays.

However, with artificial sources now able to duplicate any electromagnetic radiation that originates in the nucleus, as well as far higher energies, the wavelengths characteristic of radioactive gamma ray sources vs. other types, now completely overlap. Thus, gamma rays are now usually distinguished by their origin: X-rays are emitted by definition by electrons outside the nucleus, while gamma rays are emitted by the nucleus.

http://en.wikipedia.org/wiki/Gamma_ray

 

[mfb]

Thus, gamma rays are now usually distinguished by their origin

That has its own problems. Thorium 229 has an excitation just 8 eV above the ground state, the corresponding "gamma ray" is in the ultraviolet range.

 

[ChrisVer]

That has its own problems. Thorium 229 has an excitation just 8 eV above the ground state, the corresponding "gamma ray" is in the ultraviolet range.

Exceptional things always exist... doesn't change the fact that the heavy atoms generally tend to emit in the X-rays (keV spectra), while nuclei in general tend to emit in the MeV ranges (gamma).